This invention relates to the field of vane-type fluid-handling machines, e.g., fluid compressors and expanders. The fluid-handling machine taught by Applicant""s U.S. Pat. Nos. 5,087,183 and 5,160,252 (hereinafter the ""183 and ""252 patents) eliminated the most undesirable spatial degree of freedom of ordinary vane-type compressors by eliminating vane tip rubbing by controlling radial motion of the vane such that its tip cannot contact the stator bore but operate close enough to insure good dynamic fluid sealing. Further, Applicant""s U.S. Pat. No. 5,374,172 (hereinafter the ""172 patent) teaches a single vane (UniVane(trademark)) type fluid-handling machine with, among other features, vane tip radial motion control similar to said ""183 and ""252 patents. The disclosures of the aforesaid U.S. Pat. Nos. ""183, ""252, and ""172, as well as my co-pending U.S. patent application entitled: xe2x80x9cHigh-Speed UniVane Fluid-Handling Machinexe2x80x9d, Ser. No. 09/729,505 filed Dec. 4, 2000, are incorporated herein by reference.
Long-duration operation of the UniVane(trademark) compressor, made it clear, however, that in order to achieve exceptional long-term reliability and efficiency, its remaining spatial degree-of-freedom, axial motion, must also be eliminated. Classical mechanics provides that a solid body can have only three degrees of spatial freedom. In cylindrical coordinates, particularly convenient in the present instance, these three degrees of freedom can be represented as: r, z and xcex8; where r is the radial dimension of the vane tip, z is the axial or longitudinal dimension of both the rotor and stator, and xcex8 is the rotational (operational) dimension of both. Although no specific loads arise in the axial direction in the UniVane(trademark), the running parts nonetheless tend to oscillate or otherwise move axially in actual operation thus causing recurring back-and-forth actual contact and wear between the axial faces of the vane and the rotor as they contact the internal axially-facing static surfaces of the stator.
Further, because leakage is a function of the cube of a leakage gap, when the rotor and valve subassembly moves axially to one side, not only does wear and friction occur on that side, but the leakage gap on the non-contacting, or other end or side doubles. If, for example the free, or designed axial clearance, were 0.001xe2x80x3 (0.025 mm) per side, the total leakage doubles when the moving parts shift to one side, even though that side""s leakage will be essentially zero when contacting the static sealing face. Thus, both the rotor and the vane must to be confined to a central location such that they cannot move back and forth axially and contact the endplates of the stator housing. By confining the running parts of the UniVane(trademark) in both the radial and axial directions, the only degree of spatial freedom left is the operational direction of motion of the machine itself: rotational (or xcex8, as outlined above); the present invention solves the problem and provides the designed axial constraint of both rotor and rotor vane. The invention further permits axial constraint or adjustment of the rotor independent of the vane adjustment, and vice versa.
The need for precise sealing interface clearance control becomes especially important when a fluid-handling device cannot employ the very significant benefit of a liquid lubrication system. Such a system, through the action of the liquid lubricant, separates the moving parts (and, in effect, controls the clearances) while, simultaneously, provides a liquid leakage barrier between them. For example, a liquid lubrication system cannot be used in compressor applications for supplying air to fuel cells or to medical or food-related systems. Therefore, the highest efficiency and highest reliability fluid-handling mechanism will, by definition, be one in which the operating parts don""t engage (rub) but are close enough to provide excellent interface sealing without the benefit of a liquid lubricant. This can be achieved only with fluid-handling mechanisms that possess but a single degree of spatial freedom, i.e., rotational, so the sealing components cannot axially wander about; these desired characteristics are provided by the present invention.
As noted above, the axial motion of both the rotor and the vane of the UniVane(trademark) type fluid-handling machine must be controlled to prevent side contact with the two in-facing stator walls. Because the rotor and the vane rotate about separate (but parallel) axes, they must be controlled independently with the same precision but without mutual interference; the following reveals how such clearance-control is achieved by the present invention.